If you're comparing a Markforged Onyx Pro 3D printer Gen 2 against CNC machining or plastic injection molding, stop reading spec sheets and start asking one question: what's the total cost of a good part, including my own time and rework?
Over the last 18 months, our small manufacturing shop in New York burned roughly $47,000 on material mistakes, rushed vendor decisions, and hidden fees. Most Markforged Onyx Pro 3D printer Gen 2 reviews focus on print quality and speed. This one is different: it's a review of my errors, plus the checklist I built after them.
Why You Should Listen to Me
I've been handling manufacturing orders for nine years, mostly for medical and aerospace startups in the Northeast. In 2023, we started getting requests for continuous carbon fiber parts. In January 2024, I bought the Onyx Pro Gen 2. I made classic beginner errors—ignoring layer orientation, trusting the first quote, assuming additive meant “no setup costs.” One mistake cost us $3,200 and a week of delay. Since then, I've maintained a checklist that's caught 47 potential problems in the last 12 months.
What the Markforged Onyx Pro Gen 2 Really Does Well
Let me be clear: the printer earns its floor space. It's basically a reliable workhorse for carbon fiber reinforced parts. We printed inspection fixtures that outlasted the machined aluminum originals by months. We also printed custom end-of-arm tooling inserts for a robotics client that would've taken three weeks to machine — we had them in two days.
But the machine is only half the story. In March 2024, I approved a batch of 19 parts that looked perfect in the slicer. The load direction ran parallel to the layer lines, and they fractured during assembly. Every single one. Straight to the trash. $3,200 of material and hours—plus the rush replacement.
That was my mistake, not the printer's. But it taught me that the cheapest additive part can be the most expensive one if you skip the failure mode analysis.
Plastic Injection Molding in New York: The Hidden Fee Problem
Around the same time, we needed 500 plastic housings. I searched for manufacturing plastic injection molding in New York and got three quotes. The first: $8,000 for the mold. The second: $14,000. The third: $11,500. Being cheap, we went with the $8,000 quote.
Honestly, that was a rookie mistake. The $8,000 covered the molded part tool and nothing else. Engineering change fees: $1,800. Steel upgrade because the plastic had glass fill: $2,400. Trial shots: $950. Delivery: $410. The final bill was $18,900. The vendor didn't hide anything—I just didn't ask what was excluded.
Now I ask every vendor, “What is not included in this quote?” It's uncomfortable at first. But transparent pricing beats a low number with surprise line items every time.
Metal-Based Additive Manufacturing vs. CNC: A Test That Hurt My Ego
I really wanted to use metal based additive manufacturing for more parts. It's exciting, and it feels like the future. So I sent out a bracket design to a service bureau. They printed it in Inconel for $212 per part. It looked stunning. Then a local CNC shop quoted the same bracket for $78 per part, with a shorter lead time and tolerances we could trust.
Why? Because the bracket had no internal channels or lattice structures. It was a simple, machinable geometry. Metal AM is the right answer when you need interior features you can't mill. For straightforward parts, it's expensive and slow compared to CNC.
Which brings up the real question: how to find CNC machining work without getting burned. Here's what I've learned to ask before sending a CAD file:
- Request a DFM review before the quote, not after.
- Ask if material, deburring, and surface finish are included in the price.
- Confirm whether First Article Inspection (FAI) costs extra.
- Ask about shipping terms—expedited freight can double the final invoice.
- Get lead time in writing. Verbal promises don't survive contact with the production schedule.
In October 2024, I sent this checklist to five CNC vendors with identical specifications. The price spread was 230%. The cheapest quote was missing $1,900 in necessary extras. The second-most-expensive quote was actually the cheapest final cost—because every line item was listed up front.
When This Advice Doesn't Apply
Let me be honest about the limits. The Onyx Pro Gen 2 is not a replacement for injection molding at volume. For 500 or 5,000 identical parts, molding wins on per-unit cost. Metal AM is not a replacement for CNC when the geometry is simple. And Onyx material is not suitable for every load case—even with continuous fiber.
According to Markforged's website (accessed January 2025), Onyx has a heat deflection temperature around 145°C. But we learned not to trust that number without testing our own parts. Environmental factors, print orientation, and infill all affect the real performance.
Take all of this with a grain of salt. I'm not 100% sure that what worked for us will work for you. Your parts, volumes, and team are different. But the core habit—asking for total transparency from every supplier—has saved us more money than any single machine or material choice.
Oh, and one more thing: if you get a quote that looks too good to be true, it is. Not because the vendor is dishonest, but because something is missing—and you'll pay for it later.